Different types of wireless mobile communication devices may have multi-antenna systems. Devices, employing multiple antennas at both the transmitter and receiver, may offer increased capacity and enhanced performance for communication systems, possibly without the need for increased transmission power. Limited space in the enclosure of a device, however, may need to be considered in designing such multiple antenna assemblies. An antenna may be compact to occupy relatively small amount of space.
Furthermore, since the multiple antennas may be located close to each other, strong mutual coupling may occur between them, which can distort the radiation patterns of each antenna and degrade system performance, for example, causing an antenna element to radiate or receive an unwanted signal. A metal cover of the device may increase the undesired electromagnetic coupling between the antennas.